document.write( "Question 688891: How much of an alloy that is 10% copper should be mixed with 600 ounces of an alloy that is 90% copper in order to get an alloy that is 40% copper? \n" ); document.write( "
Algebra.Com's Answer #425731 by checkley79(3341)\"\" \"About 
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.10X+.90*600=.40(X+600)
\n" ); document.write( ".10X+540=.40X+240
\n" ); document.write( ".10X-.40X=240-540
\n" ); document.write( "-.30X=-300
\n" ); document.write( "X=-300/-.30
\n" ); document.write( "X=1000 OZ. OF 10% COPPER IS USED.
\n" ); document.write( "PROOF:
\n" ); document.write( ".10*1000+540=.40(1000+600)
\n" ); document.write( "100+540=.40*1600
\n" ); document.write( "640=640
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